In a manufacturing process for electronic devices, such as semiconductor devices, liquid crystal display devices, and organic electro-luminescent (EL) elements, a film forming process is performed to form a conductive film (CF) or an insulating film on the surface of a substrate. A plasma film forming process for forming a film on a substrate using plasma is employed in this film forming process. In a case when forming a CF film on a substrate, and further forming an insulating film on the CF film in the film forming process, there has been a problem that the fluorine atom in the CF film diffuses in the insulating film, thereby the contactablity of the CF film and the insulating film decreases. Also, there has been a problem that the insulation film may peel off due to corrosion of the insulating film by the fluorine atom diffused in the insulating film when the CF film and the insulating film are heat treated at a subsequent film forming process.
By the way, the above plasma film forming process is normally performed by a plasma film forming device. In recent years, a microwave plasma film forming device, which forms a film by generating plasma by a microwave field, has been attracting attention as a type of plasma film forming device. According to this microwave plasma film forming device, high-density plasma compared to the conventional film forming devices can be obtained, thereby the film forming process to the substrate can be performed effectively in a short time.
The microwave plasma film forming device described above is provided with, for example, a placing base to place a substrate inside a treatment vessel. And on the upper portion of the treatment vessel, provided are radial line slot antennas, and a shower ring to pass through the microwave from the radial line antennas and to supply plasma gas. Further, the microwave plasma film forming device is configured to a supply material gas for film from the wall surface of the treatment vessel.
As a plasma processing method for forming a film using the microwave plasma film forming device, for example, the following has been known. For example, Japanese Published Unexamined Patent Application No. 2005-093737 discloses a plasma processing method for forming a film on a substrate which is capable of forming a high quality film with a low temperature in a short time by optimizing the amounts of radicals and ions supplied to the substrate. Also, Japanese Published Unexamined Application No. 2006-324023 discloses a plasma film forming device capable of minimizing deformation or distortion of the shower ring by maintaining the temperature of the shower ring to a desired temperature, and improving the uniformity of an in-plane temperature of the shower ring.
Also, Japanese Published Unexamined Patent Application No. 2005-150612 discloses a plasma film forming device which prevents the gas for plasma excitation from plasmanizing before it is supplied to the treatment vessel, and appropriately generates plasma within the area of a high-frequency wave supplying side, that is, a plasma generating area.
Further, International Published Unexamined Patent Application No. 2000-74127 discloses a plasma process device capable of maintaining the stability of the plasma regardless of the type of gas used for the process because there is no film attachment on the surface of the dielectric shower ring of the microwave introduction part due to dissociation or binding of the gas for processing.
However, it is difficult to prevent the fluorine atom in the CF film formed on the substrate from diffusing in the insulating film, and also to prevent the contactablity of the CF film and the insulating film from deteriorating by using any of the methods described in the documents above.